Arsenal SLG series. I cant remember the exact one, but its a 7.62 pattern, making it an AKM base.

The AK-47 itself is a catch-all term for any 7.62 pattern AK that existed before the AKM. The AK went though several evolutions before it arrived to the "AK-47", more properly, it should be called the AKM.

Easiest way to tell a 7.62x39 and 5.45x39 AK appart is the magazine typically. The 7.62x39 round has a more sever geometrical taper to it, creating a large curvature of the magazine. The 5.45 has a less severe taper.

Here is a picture of the two side by side, top is a 5.45x39 and the bottom is a 7.62x39.